diff --git a/Documentation/trace/ftrace.rst b/Documentation/trace/ftrace.rst index 4e5b26f03d5b..d036946bce7a 100644 --- a/Documentation/trace/ftrace.rst +++ b/Documentation/trace/ftrace.rst @@ -2929,7 +2929,7 @@ Produces:: bash-1994 [000] .... 4342.324898: ima_get_action <-process_measurement bash-1994 [000] .... 4342.324898: ima_match_policy <-ima_get_action bash-1994 [000] .... 4342.324899: do_truncate <-do_last - bash-1994 [000] .... 4342.324899: should_remove_suid <-do_truncate + bash-1994 [000] .... 4342.324899: setattr_should_drop_suidgid <-do_truncate bash-1994 [000] .... 4342.324899: notify_change <-do_truncate bash-1994 [000] .... 4342.324900: current_fs_time <-notify_change bash-1994 [000] .... 4342.324900: current_kernel_time <-current_fs_time diff --git a/fs/attr.c b/fs/attr.c index 965be68ed8fa..0ca14cbd4b8b 100644 --- a/fs/attr.c +++ b/fs/attr.c @@ -48,34 +48,39 @@ int setattr_should_drop_sgid(struct user_namespace *mnt_userns, return 0; } -/* - * The logic we want is +/** + * setattr_should_drop_suidgid - determine whether the set{g,u}id bit needs to + * be dropped + * @mnt_userns: user namespace of the mount @inode was found from + * @inode: inode to check * - * if suid or (sgid and xgrp) - * remove privs + * This function determines whether the set{g,u}id bits need to be removed. + * If the setuid bit needs to be removed ATTR_KILL_SUID is returned. If the + * setgid bit needs to be removed ATTR_KILL_SGID is returned. If both + * set{g,u}id bits need to be removed the corresponding mask of both flags is + * returned. + * + * Return: A mask of ATTR_KILL_S{G,U}ID indicating which - if any - setid bits + * to remove, 0 otherwise. */ -int should_remove_suid(struct dentry *dentry) +int setattr_should_drop_suidgid(struct user_namespace *mnt_userns, + struct inode *inode) { - umode_t mode = d_inode(dentry)->i_mode; + umode_t mode = inode->i_mode; int kill = 0; /* suid always must be killed */ if (unlikely(mode & S_ISUID)) kill = ATTR_KILL_SUID; - /* - * sgid without any exec bits is just a mandatory locking mark; leave - * it alone. If some exec bits are set, it's a real sgid; kill it. - */ - if (unlikely((mode & S_ISGID) && (mode & S_IXGRP))) - kill |= ATTR_KILL_SGID; + kill |= setattr_should_drop_sgid(mnt_userns, inode); if (unlikely(kill && !capable(CAP_FSETID) && S_ISREG(mode))) return kill; return 0; } -EXPORT_SYMBOL(should_remove_suid); +EXPORT_SYMBOL(setattr_should_drop_suidgid); /** * chown_ok - verify permissions to chown inode @@ -440,7 +445,7 @@ int notify_change(struct user_namespace *mnt_userns, struct dentry *dentry, } } if (ia_valid & ATTR_KILL_SGID) { - if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) { + if (mode & S_ISGID) { if (!(ia_valid & ATTR_MODE)) { ia_valid = attr->ia_valid |= ATTR_MODE; attr->ia_mode = inode->i_mode; diff --git a/fs/fuse/file.c b/fs/fuse/file.c index cc95a1c37644..2b19d281351e 100644 --- a/fs/fuse/file.c +++ b/fs/fuse/file.c @@ -1295,7 +1295,7 @@ static ssize_t fuse_cache_write_iter(struct kiocb *iocb, struct iov_iter *from) return err; if (fc->handle_killpriv_v2 && - should_remove_suid(file_dentry(file))) { + setattr_should_drop_suidgid(&init_user_ns, file_inode(file))) { goto writethrough; } diff --git a/fs/inode.c b/fs/inode.c index 3811269259e1..079b64f9b756 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -1869,7 +1869,8 @@ EXPORT_SYMBOL(touch_atime); * response to write or truncate. Return 0 if nothing has to be changed. * Negative value on error (change should be denied). */ -int dentry_needs_remove_privs(struct dentry *dentry) +int dentry_needs_remove_privs(struct user_namespace *mnt_userns, + struct dentry *dentry) { struct inode *inode = d_inode(dentry); int mask = 0; @@ -1878,7 +1879,7 @@ int dentry_needs_remove_privs(struct dentry *dentry) if (IS_NOSEC(inode)) return 0; - mask = should_remove_suid(dentry); + mask = setattr_should_drop_suidgid(mnt_userns, inode); ret = security_inode_need_killpriv(dentry); if (ret < 0) return ret; @@ -1920,7 +1921,7 @@ int file_remove_privs(struct file *file) if (IS_NOSEC(inode) || !S_ISREG(inode->i_mode)) return 0; - kill = dentry_needs_remove_privs(dentry); + kill = dentry_needs_remove_privs(file_mnt_user_ns(file), dentry); if (kill < 0) return kill; if (kill) diff --git a/fs/internal.h b/fs/internal.h index 45cf31d7380b..46df4ce58e87 100644 --- a/fs/internal.h +++ b/fs/internal.h @@ -149,7 +149,7 @@ extern int vfs_open(const struct path *, struct file *); */ extern long prune_icache_sb(struct super_block *sb, struct shrink_control *sc); extern void inode_add_lru(struct inode *inode); -extern int dentry_needs_remove_privs(struct dentry *dentry); +int dentry_needs_remove_privs(struct user_namespace *, struct dentry *dentry); bool in_group_or_capable(struct user_namespace *mnt_userns, const struct inode *inode, kgid_t gid); diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c index fc5f780fa235..92182d4be247 100644 --- a/fs/ocfs2/file.c +++ b/fs/ocfs2/file.c @@ -1994,7 +1994,7 @@ static int __ocfs2_change_file_space(struct file *file, struct inode *inode, } } - if (file && should_remove_suid(file->f_path.dentry)) { + if (file && setattr_should_drop_suidgid(&init_user_ns, file_inode(file))) { ret = __ocfs2_write_remove_suid(inode, di_bh); if (ret) { mlog_errno(ret); @@ -2282,7 +2282,7 @@ static int ocfs2_prepare_inode_for_write(struct file *file, * inode. There's also the dinode i_size state which * can be lost via setattr during extending writes (we * set inode->i_size at the end of a write. */ - if (should_remove_suid(dentry)) { + if (setattr_should_drop_suidgid(&init_user_ns, inode)) { if (meta_level == 0) { ocfs2_inode_unlock_for_extent_tree(inode, &di_bh, diff --git a/fs/open.c b/fs/open.c index 5e322f188e83..e93c33069055 100644 --- a/fs/open.c +++ b/fs/open.c @@ -54,7 +54,7 @@ int do_truncate(struct user_namespace *mnt_userns, struct dentry *dentry, } /* Remove suid, sgid, and file capabilities on truncate too */ - ret = dentry_needs_remove_privs(dentry); + ret = dentry_needs_remove_privs(mnt_userns, dentry); if (ret < 0) return ret; if (ret) @@ -671,10 +671,10 @@ retry_deleg: newattrs.ia_valid |= ATTR_GID; newattrs.ia_gid = gid; } - if (!S_ISDIR(inode->i_mode)) - newattrs.ia_valid |= - ATTR_KILL_SUID | ATTR_KILL_SGID | ATTR_KILL_PRIV; inode_lock(inode); + if (!S_ISDIR(inode->i_mode)) + newattrs.ia_valid |= ATTR_KILL_SUID | ATTR_KILL_PRIV | + setattr_should_drop_sgid(mnt_userns, inode); error = security_path_chown(path, uid, gid); if (!error) error = notify_change(mnt_userns, path->dentry, &newattrs, diff --git a/include/linux/fs.h b/include/linux/fs.h index be9be4a7216c..9601c2d774c8 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -3133,7 +3133,7 @@ extern void __destroy_inode(struct inode *); extern struct inode *new_inode_pseudo(struct super_block *sb); extern struct inode *new_inode(struct super_block *sb); extern void free_inode_nonrcu(struct inode *inode); -extern int should_remove_suid(struct dentry *); +extern int setattr_should_drop_suidgid(struct user_namespace *, struct inode *); extern int file_remove_privs(struct file *); extern void __insert_inode_hash(struct inode *, unsigned long hashval);